An attempt to improve carrier mobility in an inversion layer by applying a stress to a channel region in a planar FET has been made. For example, a method of applying a stress to a channel region by etching a part of a drain region and/or source region and filling therein a semiconductor having different lattice constant is used (for example, JP. 2007-129235).
However, in a fin-type MOS transistor (hereinbelow, Fin FET), a material having different lattice constant can be buried in a part of a fin, but it is difficult to effectively apply a stress to the channel region.